Why Are Fasting Blood Sugars Higher Than Postprandial?

High pre-meal blood sugar levels could indicate a health problem.

Whether you’ve been diagnosed with diabetes or simply monitor your blood sugar levels to track your health, fasting and postprandial blood glucose levels are frequently measured. Since your fasting blood sugar is taken before eating a meal and your postprandial blood sugar is taken after the meal, your fasting level should be lower than your postprandial level. But if the numbers are reversed and your fasting blood sugar levels are higher than your postprandial levels, it could indicate a serious health problem.

Know the Norms

The American Diabetes Association, or ADA, recommends specific pre-meal and post-meal blood sugar ranges for healthy adults. According to the ADA, fasting blood sugar should fall between 70 to 130 milligrams per deciliter of blood. After you eat, this number should increase as your body absorbs sugar molecules from food. However, the ADA recommends that the postprandial blood glucose level stays at or below 180 milligrams per deciliter.

Dawn Phenomenon

The dawn phenomenon is a medical condition characterized by a blood sugar spike that occurs early in the morning, reports MayoClinic.com. The sugar surge could be related to an inadequate dose of insulin the night before or eating too many carbs before bed. But the spike might also be related to natural body fluctuations that occur during sleep. During the night, newly released hormones might increase your body’s resistance to insulin, which ultimately impacts your body’s ability to absorb sugar into the cells, resulting in high sugar levels in the blood.

Insulin Resistance

Insulin resistance is a daily problem for people with diabetes. Insulin is responsible for pushing sugar out of the bloodstream and into the cells to be used as energy. But when the cells are resistant to insulin’s action, the sugar gets stuck in the bloodstream and the cells starve. This problem is further compounded at night, when the liver naturally releases small amounts of glucose into the bloodstream to hold you over until you’re next meal. And since the diabetic liver tends to release more blood sugar than necessary, it results in an excessively high blood sugar level before you even think about eating.

Call Your Doc

Getting one random fasting blood sugar result that's high before you eat probably isn’t a significant concern. However, if you tend to notice a frequent pattern of high pre-meal blood sugar readings, call your doctor. Along with your blood sugar test times and results, your physician will also probably ask about your symptoms, eating and exercise habits, recent stressors, illnesses and medication usage.